Method of making ground rods



Dec. 27, 1932. B NMCK 1,891,943

METHOD OF MAKING GROUND RODS Filed July 22, 193].

' INVENTOR Patented Dec. 27, 1932 UNITED s'riATEs PATENT' OFFICE FRANCISB. NIMICK, OF COB-AOPOLIS, PENNSYLVANIA, ASSIGNOR TO COLONIAL STEELGOHPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA mnonor MAKING enonnn nons Application filed July 22, 1931. Serial No.552,403.

My invention relates more particularly to ground rods such as areemployed in connection; with electrical transmission lines, but is alsosusceptible of use in various other ways.

Ground rods frequently consist of bars which are driven into the groundto serve as anchoring posts and also as ground conductors. Conductorbars have heretofore been composed of a core or main body portion ofsteel or the like and a sheath or sleeve of copper or other material,the steel being employed for the purpose of strength and the copper byreason of its conductivity and noncorrosive character, but suchcomposite bars have been commonly either square or round in crosssection.

One object of my inventionis to provide a ground'rod of the typereferred to, which for a given cross sectional area, has relative- 2 liygreat surface area and hence greater con-' ctivity than bars of theforms heretofore employed, and which also is possessed of greatermechanical strength.

Another object of my invention is to rovide ound rods of generallyimproved 0 aracteristics in the way of form and eflicienc In order topermit of the clear understan ing of my invention, I have shown variousfeatures thereof in the accompanying draw- 80 ing, wherein Figure 1 is aperspective viewv of my rod at a preliminary stage in the process offorming the same; Fig. 2 isa similar view showing another form ofcomposite blank from which ,a completed ground rod '8 may be formed;Fig. 3 is an elevational perspective view of a feeder rod formed from acomposite blank shaped according to either Fig. 1 or Fig. 2, and Flg. 4is across sectional view of the rod of Fig. 3.

While I hereinafter describe a ground rod that is ribbed, it will beunderstood that the rod may be fluted, grooved, or otherwise shaped toprovide an exposed surface that is relatively great, compared to thecross secg tional area of the bar.

Referring to Fig. 1, a bar 4 of steel or the like, is covered by acopper sleeve or sheath 5, as by a welding operation well-known in theart, or by a combined welding and rolling or drawing operation. Again,the copper may be electrically deposited upon the steel. In any case, Ihave] structure wherein the core or body portion 4 possesses greatstrength, as in the case of steel, which can be driven into the ground,and a structure wherein the sheath 5 serves to effectively conductelectrical currents to the ground and to protect the bar 4: againstcorrosion, etc.

amount of metal as in its original form, there 'IS, nevertheless, agreater area of the sheath 5 exposed than in the case of the structureof Fig. 1, thus providing for greater surface contact with the groundand better electrical conductivity. Furthermore, the longitudinal ribsincrease the mechanical strength of the bar as shown'in Fig. 3, relativeto the strength present in the bar .of Fig. 1. This increased strengthis particularly desirable, because the" rod must fre uently be driveninto hard ground, and furt ermore it has in-.

creased resistance to transverse stresses.

The blank of Fig. 1 is heated to forginlfi or rollin temperature tofacilitate the ro ng and s a'ping thereof as above-described.

The blank of Fig. 2 is shaped to the form shown in Figs. 3 and 4, byheating and rolling or otherwise shapin it, the end of the copper sleeve511 being rawn to a point to completely enclose the end of the core bar40. In other words, a rod formed from the blank of Fig. 2 will have theappearance of the rod shown in Figs. 3and 4, with the co per comletelyenclosing the lower end 0 the core ar 4.

A conductor wire 6 leading from a line or structure to be grounded isplaced within one of the flutes of the bar, and may be securelymaintained therein in any suitable manner asby coiling a wire snuglyaround the round rod and the ground wire, or by suitaile clamping meanssuch as an ordinary hose clamp.

The placing groove provi es of the ground wire 6 in a an extendedelectrical contact between it and the ground rod much greater than inthose cases where the ound wire is simply secured against the si e of acircular or atside ground rod.

5 I claim as my invention 1. The method of making ground rods whichcomprises covering a hard metal bar with a close-fitting tubular sheaththat is open at one end and is of more ductile metal that has highelectrical conductivity, heating the composite structure to forgingtemperature and shaping the composite structure to form ribs extendinglongitudinally thereof, and to cause said ductile metal to completelyenclose the said end of the said bar.

2. The method of making ground rods which comprises covering a hardmetal bar with a close-fitting tubular sheath that is open at one endand is of more ductile metal that has high electrical conductivity,heating the composite structure to forging temperature and shaping thecomposite structure to form ribs extending longitudinally thereof, andto cause said ductile metal to com-' pletely enclose the said end of thesaid bar, an additional forgingoperation being performed on said end todraw it to a point.

3. The method which comprises cover' a hard metal bar with aclose-fitting sheat of more ductile metal, and which is open at one end,heating the composite structure to forging temperature, rolling thecomposite bar toward said end, to form ribs extending longitudinallythereof and to effect elongation of the sheath relative to the bar, andcompressing the said end of the composite bar to effect pointing thereofand cause the enclosure of the core point by the sheath.

4. The method which com rises coverin a hard metal bar with aclose-hitting sheath 0 more ductile metal and which is open at one end,rolling the composite bar toward said end to efiectelongation thereof,and compressingsaid end of the composite bar to efiect pointing thereofand cause the enclosure 0 the core point by the sheath.

5. The method which comprises covering a cylindrical bar of relativelyhard metal with a close-fitting cylindrical sheath of more ductilemetal, heating the composite structure to forging temperature, appl gradially inward forging pressure to said b dr from 0posite sides thereofon two diametral lines sposed at right angles to one another, ef-

fecting elongation o the sheath relative to the bar, and compressing thecomposite structure near one end thereof to produce a point thereon andcause the enclosure of the core p point by the sheath.

In testimony whereof I, the said FRANCIS B. Nnnox, have hereunto set myhand.

FRANCIS B. NDHGK.

